北方农牧交错带不同管理类型下草场治理效果研究

采用样方法选取6块草场:老封育草场(E)、中封育草场(E1)、新封育草场(E2)、天然草场(TR)、退耕还草(TG)和撂荒地(LH)对宁夏盐池不同管理类型下的的草场治理效果进行了研究.以重要值为基础,通过α多样性指数、β多样性指数以及生物量的比较,对不同管理类型下的草场治理效果进行综合评价.结果表明:(1) 不同草场类型中,天然草场由于人为干扰较小,SW多样性指数、SP优势度指数均为最好,均匀度指数以退耕还草为最大;(2) 退耕还草的群落组成最接近于天然草场;(3) 不同草场的地上生物量中,最大的为退耕还草,其次为天然草场,在围栏封育草场中,老封育区的地上生物量是最小的.围栏封育和退耕还草在当地草场恢复中都是行之有效的方式.随着围栏封育年限的延长,草场出现退化现象,其各多样性指标都比早期封育时低.相比较于围栏封育,退耕还草在当地的优越性更加明显.

Survey on the Effects of Management Alteration on Grassland in Agropastural Ecotone of North China

Method of sampling plot has been used to investigate treatment effects of different management categories on grassland in Yanchi, Ningxia Hui Autonomous Region. Six kinds of grasslands have been selected, which were early-time enclosed grassland (E), middle-time enclosed grassland (E1), newly enclosed grassland (E2), natural grassland(TR), grain for green land(TG) and abandoned land(LH). On the basis of important value, evaluation in improvement of grassland environment has been done through α-diversity index, β-diversity index and biomass effectiveness. The results showed that: (1) due to little human disturbances, natural grassland performanced the best in terms of SW-diversity index and SP-dominance index compared with the others, and grain for green land has the biggest evenness index; (2) on the study of grassland similar test, community composition of grain for green land was most likely to natural grassland; (3) based on the study of biomass, grain for green land achieves the highest biomass, biomass of natural land was ranked as the second. Among fencing grasslands, early-time enclosed grassland had the lowest aboveground biomass. As a result, fencing and grain for green were effective methods to generate grassland restoration. As fencing time went by, grassland came to degradation with the sign that diversity indices turn to decrease compared with early time. Method of grain for green behaved significantly better than fencing.